Co-production of high purity isobutane and butene-1 from mixed C4s

Abstract

Systems and processes disclosed may be used to produce a high purity isobutane stream and a high purity 1-butene stream from mixed C4 streams having disparate starting compositions.

What is claimed: 
     
       1. A process for the co-production of high purity isobutane and high purity 1-butene streams, the process comprising:
 providing a first mixed C 4  stream and a second mixed C 4  stream, each comprising isobutene, isobutane, 1-butene, and 2-butene, and wherein the first mixed C 4  stream has a higher concentration of isobutane than the second mixed C 4  stream; 
 feeding the first mixed C 4  stream and methanol, as a reactant or selectivator, to a first reaction system for converting isobutene contained therein to methyl tert butyl ether or isobutene dimers; 
 feeding the second mixed C 4  stream and methanol, as a reactant or selectivator, to a second reaction system for converting isobutene contained therein to methyl tert butyl ether or isobutene dimers; 
 separating an effluent from the first reaction system in a first separation system, including a water wash system, to recover a first lights stream comprising 1-butene, 2-butene, isobutane, a first methanol+water stream, and a first heavy stream comprising the methyl tert butyl ether or the isobutene dimers; 
 separating an effluent from the second reaction system in a second separation system, including a water wash system, to recover a second lights stream comprising 1-butene, 2-butene, and isobutane, a second methanol+water stream, and a second heavy stream comprising the methyl tert butyl ether or the isobutene dimers; 
 feeding the first and second methanol+water streams to a methanol recovery system to separate methanol from the water and returning at least a portion of the methanol to either or both the first and second reaction systems; 
 feeding the second lights stream to a separation system for recovering an isobutane containing stream, a 1-butene stream, and a first heavy C 4  stream comprising n-butanes and 2-butene; 
 feeding the isobutane containing stream and the first lights stream to a separation system for recovering an isobutane stream and a second heavy C 4  stream comprising n-butanes and 2-butene. 
 
     
     
       2. The process of  claim 1 , further comprising separating dimethyl ether from the isobutane stream. 
     
     
       3. The process of  claim 1 , wherein the isobutane stream has a purity of at least 99 wt % and wherein the 1-butene stream has a purity of at least 99 wt %. 
     
     
       4. The process of  claim 1 , further comprising feeding a hydrocarbon stream to a fluid catalytic cracking process or a residue fluid catalytic cracking process and recovering the first mixed C 4  stream, wherein the first mixed C 4  stream has a concentration of isobutane of at least 20 wt %. 
     
     
       5. The process of  claim 4 , further comprising feeding a hydrocarbon stream to a steam cracking process and recovering the second mixed C 4  stream, wherein the second mixed C 4  stream has a concentration of isobutane of less than 5 wt %. 
     
     
       6. The process of  claim 5 , wherein the first mixed C 4  stream has a concentration of isobutene of less than 25 wt %, and wherein the second mixed C 4  stream has a concentration of isobutene of at least 30 wt %. 
     
     
       7. A system for the co-production of high purity isobutane and high purity 1-butene streams, the system comprising:
 a first mixed C 4  stream and a second mixed C 4  stream, each comprising isobutene, isobutane, 1-butene, and 2-butene, and wherein the first mixed C 4  stream has a higher concentration of isobutane than the second mixed C 4  stream; 
 a first methanol stream and a second methanol stream; 
 a first reaction system configured to receive the first mixed C 4  stream and the first methanol stream and to react the first mixed C 4  stream and methanol, as a reactant or selectivator, converting isobutene contained therein to methyl tert butyl ether or isobutene dimers; 
 a second reaction system configured to receive the second mixed C 4  stream and the second methanol stream and to react the second mixed C 4  stream and methanol, as a reactant or selectivator, converting isobutene contained therein to methyl tert butyl ether or isobutene dimers; 
 a first separation system, including a water wash system, for separating an effluent from the first reaction system to recover a first lights stream comprising 1-butene, 2-butene, isobutane, a first methanol+water stream, and a first heavy stream comprising the methyl tert butyl ether or the isobutene dimers; 
 a second separation system, including a water wash system, for separating an effluent from the second reaction system to recover a second lights stream comprising 1-butene, 2-butene, isobutane, a second methanol+water stream, and a second heavy stream comprising the methyl tert butyl ether or the isobutene dimers; 
 a common methanol recovery system for receiving the first and second methanol+water streams to separate methanol from the water and a flow line for returning at least a portion of the methanol to either or both the first and second reaction systems; 
 a first lights separation system for receiving the second lights stream and recovering an isobutane containing stream, a 1-butene stream, and a first heavy C 4  stream comprising n-butanes and 2-butene; 
 a second lights separation system for receiving the first lights stream and for recovering an isobutane stream and a second heavy C 4  stream comprising n-butanes and 2-butene. 
 
     
     
       8. The system of  claim 7 , further comprising a first mixer for mixing the first and second heavy C 4  streams, and a second mixer for mixing the first and second heavy streams. 
     
     
       9. The system of  claim 7 , wherein each of the first and second reaction systems is configured to produce isobutene dimers. 
     
     
       10. The system of  claim 7 , wherein each of the first and second reaction systems is configured to produce methyl tert butyl ether. 
     
     
       11. The system of  claim 7 , wherein the first reaction system includes a fixed bed reactor, or two or more fixed bed reactors in series or in parallel, followed by a catalytic distillation reactor. 
     
     
       12. The system of  claim 7 , wherein the second reaction system includes a fixed bed reactor, or two or more fixed bed reactors in series or in parallel, followed by a catalytic distillation reactor.